From c350688e2ae28a84d07208c97c8e324d77199af8 Mon Sep 17 00:00:00 2001
From: Abivarman <abivarman.kandiah@etu.hesge.ch>
Date: Thu, 9 Dec 2021 13:29:29 +0100
Subject: [PATCH] Lagrange don't work yet

---
 reed_solomon.py | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/reed_solomon.py b/reed_solomon.py
index 3a36f11..870d394 100644
--- a/reed_solomon.py
+++ b/reed_solomon.py
@@ -5,8 +5,27 @@ def get_possibilities(l: list):
 	pass
 
 def lagrange_compute(l: list) -> polynome:
-	pass
+	list_s = [0] * len(l)
+	list_p = [1] * 2 + [0] * (len(l)-2)
+	sum_poly = polynome(list_s)
+	product_poly = polynome(list_p)
+
+	for x_i, y_i in enumerate(l):
+		for x_j, y_j in enumerate(l):
+			if x_j != x_i:
+				product_poly = product_poly.mul(polynome([(y_i * (0-x_j)) /(x_i - x_j) , y_i / (x_i - x_j)]))
+				#product_poly.show()
+		sum_poly = sum_poly.add(product_poly)
+		#sum_poly.show()
+		product_poly = polynome(list_p)
+	return sum_poly
 
 def check_nb_error(l: list, p: polynome) -> int:
 	pass
 
+if __name__ == '__main__':
+	list_ = [1, 2, 3]
+	print(list_)
+	poly = lagrange_compute(list_)
+	poly.show()
+	#print(poly.evaluate(0))
\ No newline at end of file
-- 
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